In the art of printing, it is desirable that the printing device know the size of the paper, or media, in the supply tray. Without paper size information, an error can occur during printing if the paper size requested is not the same as the paper size in the supply. If the printing system knows the paper size in the supply tray, the user can be notified that the present paper supply does not agree with the requested size, thereby, reducing the likelihood of an error.
Prior to the present invention, several methods of conveying the contents of a paper tray to the printing device have been developed. For example, a unique tray for each size of paper that the printing device can accommodate will insure that only one size of paper can be inserted in the tray. The primary disadvantage with this approach is increased cost in molding numerous size and configured trays. Additional disadvantages include increased cost in maintaining inventory of these numerous trays. For the user, they must accommodate storage of those trays not presently in use. Also, the user generally must purchase, at an additional cost, trays which are not initially provided with the printer.
Another approach, allows the manufacturer to manufacture one type of paper tray that can be configured for the various sizes of paper. This approach reduces manufacturing cost by requiring one molding for all paper trays. However, it requires that the user indicate to the printer the size of paper in the tray. A common method of indicating to the printer the size of paper in the tray requires the user to actually "punch out" a particular location in the paper tray. Once punched out, the tray is permanently configured for that particular paper size. If the user wishes to use a different paper size, the user must purchase a new tray.
Yet another approach to solving this problem requires the user to rotate a knob or the like on the tray to convey the size of the paper in the tray to the printer. The knob, in turn, manipulates levers located on the side of the printer tray. When the paper tray is installed into the printer, the levers actuate switches on the printer thereby communicating the size of the paper the user has indicated. No feedback exists to insure that the paper size selected is the same as the paper in the tray.